Postoperative factors affecting neurological recovery after surgery for cervical spondylotic myelopathy

Object. Many prognostic factors associated with surgery for cervical spondylotic myelopathy (CSM) have been detailed in the literature. All of these factors, however, are defined preoperatively. If it is possible to clarify factors influencing surgical results that can be modulated after surgery, then the overall results of surgery may improve. The purpose of this study was to elucidate such postoperative factors affecting neurological recovery. Methods. The authors assessed the surgical outcomes obtained in 183 patients with CSM who underwent expansive open-door laminoplasty between 1993 and 2004 and who underwent follow up for a minimum of 1 year. They classified the cases into two groups according to the degree of neurological recovery: an excellent recovery group, comprising patients in whom the recovery rates were greater than 75%, and a poor recovery group, composed of patients in whom the recovery rates were lower than 30%. Comparisons of various clinical and imaging parameters revealed that the mean age at surgery was significantly lower in patients in the excellent recovery group than that in the poor recovery group. Therefore, the authors repeated the same analyses after adjustment for age. Postoperative cervical range of motion (ROM) was significantly more reduced in the excellent recovery group than in the poor recovery group. There was a significant positive correlation between reduced cervical ROM and recovery rate in the poor recovery group. Conclusions. Dynamic stress may deteriorate functional recovery of the degenerated spinal cord even after sufficient decompression. Postoperative preservation of cervical ROM may not always be beneficial for neurological recovery in patients with CSM.